There is an existential conundrum afoot here - was this act a true error or was it a clever ploy to prevent Phil from seeing some news that might upset him? Despite the fact that Phil wants Marm dead, Marm feels nothing but compassion for his asshat owner, no matter what may happen. He's like the Doggy Lama.
And keeping in that spirit, did what he could (while enduring likely ridicule) to keep his owner's well-being at the forefront.
Either that or Marm really is losing it.